Question

In an arithmetic sequence $1,-2,-5,-8$ ....., then find the ${12}^{th}$ term.

• A. $-30$
• B. $-32$
• C. $33$
• D. $34$

Answer 1

Answer: (B)

$-32$

${12}^{th}$ term of the A.P. is $a_{12}=a+(n-1)d$
Given series is $1,-2,-5,-\mathrm{8...}$

Here $a=1,d=-3,a_{12}=?$

Since $a_n=a+(n-1)\left(d\right)$
Therefore, $a_{12}=1+(12-1)(-3)$
$a_{12}=1+11\times (-3)$
$a_{12}=1-33$
$\Rightarrow a_{12}=-32$